Seedbed for growing vegetation

ABSTRACT

An artificial seedbed used in growing vegetation. The artificial seedbed comprises a base layer formed of a biodegradable product having a porosity and wet density that permit a root of the desired vegetation to penetrate the base layer and establish the vegetation for growing. The artificial seedbed also comprises an intermediate layer comprising a plurality of seeds for use in growing the desired vegetation. A cover layer cooperates with the base layer to form an envelope about the intermediate layer. The cover layer can be coextensive with the base layer and secured to the base layer by a bonding agent. The cover layer is formed of the same or different biodegradable product as the base layer. The material used in the cover layer permits the sprouting vegetation to penetrate it during the growing process.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of prior application Ser. No.10/776,331 filed Feb. 12, 2004, which claims the benefit of priorprovisional Application Ser. No. 60/446,514 filed Feb. 12, 2003. Thefull disclosures of the prior applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to an article and method used in growingvegetation and, more particularly, to a seedbed and method for growingvegetation by applying seeds and fertilizer to a planting area andmaintaining nutrients within this planting area in order to promotegermination and growth of predetermined vegetation.

BACKGROUND OF THE INVENTION

Grass seed is sown by various known procedures. These procedures includehand seeding, “hydro-seeding” and using mats that form artificialseedbeds. Hand seeding is an old and well-known way of applying grassseed to the soil. According to the hydro-seeding method, grass seeds aremixed in a dissolved fiber solution and are dispersed on the surface ofthe ground. In the methods that employ a mat as an artificial seedbed,the mat is placed on top of the soil in order to grow and keepgerminated grass warm and moist.

Many forms of artificial seedbeds, including seed mats and carpets,intended for growing grass and other forms of vegetation are known inthe art. A conventional such seed mat is disclosed in U.S. Pat. No.4,190,981 to Muldner. This conventional seed mat includes a base layerof water pervious web material, a bed of seeds and compressed peatparticles as a middle layer, and an upper layer comprising a fibrous,porous veil. However, this upper layer does not have sufficient wetstrength to support and position the seeds after watering commences.Also, the upper layer can prematurely degrade, thereby exposing andfailing to protect young seedlings from other elements and birds.

It is therefore an object of the present invention to provide animproved artificial seedbed, in effect, an engineered seedbed withpredetermined physical properties that enhances safe sprouting andgrowth of young vegetation. It is also an object of the presentinvention to provide an artificial seed bed with a lower layer that willbe porous enough to allow roots to extend through it, but yet strongenough to support the seeds and retain some of the temperature andhumidity of the soil around the seeds during seed germination andgrowth. It is a further object of this invention to provide anartificial seedbed with an upper layer that has a density and porositythat allows extensive sprouting of the shoots from the seed, while stillbeing strong enough to protect these sprouting shoots from theirenvironment.

SUMMARY OF THE INVENTION

The present invention includes a convenient article and effective methodfor applying seed and fertilizer to a large area in a one-step processin order to cause the growth of a plant such as grass. In oneembodiment, the invention includes a rolled product that carries seedand fertilizer contained in a biodegradable matrix of cellulose fibersand biodegradable binding adhesives. This matrix will allow for easyapplication and will initially protect the seeds, but will quicklycompost into the soil and allow for normal turf maintenance in 4-6weeks.

The seedbed can be used in residential applications and in commercialapplications such as golf course construction and maintenance androadway median maintenance as well as private home lawn and gardenapplications. Unlike conventional turf sodding or seeding practices, thepresent invention is less labor-intensive with respect to its lay-downand maintenance. The seedbed contains fertilizers eliminating theadditional labor required for fertilizer laydown with conventionalseeding and sodding methods. It also produces improved seed germinationrelative to conventional broadcast seeding methods and full groundcoverage for improved erosion control that reduces the potential forserious environmental degradation of adjacent streams and wetland areas.Additionally, the full ground coverage provided by the present inventionprovides improved weed control that reduces and in some circumstanceseliminates the need for pesticide applications. The stabilizationprovided by the layers of the laminate prevents migration due to windand rain, especially on sloping terrains, thereby eliminating the needfor expensive reworking. Also, the decomposition of cellulose addsorganic matter to the base soil enhancing healthy plant growth andsustainability. In certain embodiments, the seedbed contains onlynatural, biodegradable components thereby eliminating the deposition ofpossibly undesirable synthetic materials in the environment.Additionally, certain embodiments can include a soil contacting layerthat includes a conventional soil conditioner.

An embodiment according to an aspect of the present invention includesan article for use in growing vegetation. The article comprises a baselayer formed of a biodegradable product having a porosity and wetdensity that permit a root of the vegetation to penetrate the base layerand establish the vegetation for growth. The article also comprises anintermediate layer comprising a plurality of seeds for use in growingthe vegetation. The article further comprises a cover layer that iscoextensive with the base layer and secured to the base layer by abonding agent. The cover layer is formed of the same biodegradableproduct as the base layer and has the same porosity and wet density asthe base layer such that sprouting vegetation is capable of penetratingthe cover layer.

Another aspect of the present invention comprises an article for use ingrowing vegetation comprising a base layer formed of a biodegradablenatural fiber having a basis weight of about 23 to about 300 grams persquare meter and a wet density of at least about 0.05 grams per cubiccentimeter, and a cover layer formed of biodegradable natural fibershaving a basis weight of about 13 to about 150 grams per square meterand a wet density of about 0.05 to about 0.20 grams per cubiccentimeter. The article also comprises a biodegradable bonding agent forsecuring the base layer to the cover layer.

A further aspect of the present invention includes an article for use ingrowing vegetation comprising a base layer formed of wood-derivedcellulose fibers, and a cover layer formed of biodegradable naturalfibers. The cover layer has a different porosity, a different basisweight and a different density compared to the base layer. The articlealso comprises an intermediate layer between portions of said base layerand said cover layer. The intermediate layer includes a plurality ofseeds for growing the vegetation. Further, the article comprises abonding agent for securing the base layer to the cover layer such thatthe cover layer and base layer are sealed together to contain the seedsbetween the base layer and cover layer.

The present invention also includes a method of making the articleaccording to an aspect of the present invention. The method comprisesthe steps of providing the base layer formed of biodegradable naturalfibers, providing the cover layer formed of biodegradable natural fibersand applying seeds to one of the base layer and the cover layer suchthat the seeds are distributed on a predetermined portion of the layerto which they are applied. The method also includes the steps ofapplying the bonding agent to at least one of the layers and securingthe cover layer to the base layer such that the cover layer and the baselayer form an enclosure around the seeds.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of the artificial seed bed according to thepresent invention;

FIG. 2 illustrates a laminating process according to the presentinvention;

FIGS. 3-5 show test results for samples of the artificial seedbedaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, the present invention comprises a simulatedseedbed 10 including a plurality of layers. This seedbed 10 can bedelivered as a rolled or folded article and is used for growingvegetation. As used herein, the term “vegetation” relates to plants thatgrow from seeds. Examples of vegetation include grass, vegetable plants,vegetable trees, fruit plants, fruit trees and flowering plants that donot produce either edible fruits or vegetables. However, for ease ofexplanation and understanding, the artificial seedbed 10 according tothe present invention will be explained herein as it relates to grassseed. It is understood that the embodiments and concepts of the seedbed10 discussed herein also apply to seedbeds 10 when they include seedsused to grow vegetation other than grass.

As shown in FIG. 1, the seedbed 10 includes a base layer 20, anintermediate layer 30 and a cover layer 40. The materials used to formthe layers 20, 40 preferably include natural fibers that arebiodegradable. Among the natural fibers suitable for use in accordancewith the present invention are jute fiber, palm fiber, peat, sisal,coconut fiber and wood fiber. In an embodiment including jute fibers,the layer, for example cover layer 40, containing the jute fibers couldhave a basis weight of about 10 ounces per yard square. In anotherembodiment, the base layer 20 and cover layer 40 are each formed of anatural, biodegradable product including wood-derived cellulose fibers,such as a paper product or a pulp product. The substrate 25 of layer 20and substrate 45 of layer 40 are each formed of a different paper orpulp product and form a sealed envelope around layer 30.

The substrates 25, 45, and thus layers 20, 40, can be formed using oneor a combination of the following known paper product forming processes:airlaid, wet laid, dryformed and thermoforming. In an embodiment, thewet laid tissue and toweling substrates have minimal wet-strength added.In a first airlaid embodiment, the airlaid substrates are bonded duringa conventional airlaid process using known latex or synthetic fibersthat binds to the cellulose. These binders are non-biodegradable and maybe included in varying amounts to control the degradation of one or moreof the layers 20, 40. In another airlaid embodiment, the presentinvention includes completely biodegradable starch-based binders. Forexample, the bonding agents can include a starch-based adhesive, such aspotato starch, modified cellulose or polyvinyl alcohol. The starchbinder, for example, will provide biodegradability while still providinggood dry strength to its respective layer during field application. Inan embodiment, a layer of wet-strength material is included in theseedbed 10 to provide a compromise between biodegradability anddurability.

According to the invention, the materials used to form the base layer 20and cover layer 40 have a low enough basis weight, low enough densityand high enough porosity to allow good penetration of the grass rootsand shoots, respectively. In an embodiment, the basis weights for wetlaid products used for base layer 20 and cover layer 40 can range fromabout 10 to 100 pounds per 3000 square feet. Another preferred range isfrom about 13 to 50 pounds per 3000 square feet. Additionally, the basisweight range for airlaid products used for both the base layer 20 andthe cover layer 40 can be from about 50 to 500 grams per square meter.The above-discussed layers 20, 40 each have porosity in the range ofabout 25-500 CFM/ft2. The tensile strength of the layers 20, 40 issufficient to allow the seedbed 10 to be applied without breaking. In anembodiment, the tensile break strength should be between about 2 to 50N/5 cm and have a tensile elongation of between about 1 to 20%. In atleast one of the disclosed embodiments, the layers 20, 40 arebiodegradable to the point that it will allow normal mowing in 4-6 weeksof its application. Additionally, the layers 20, 40 have a coherentenough matrix to prevent their material and the intermediate layer 30from being washed away in rainy conditions.

In an embodiment, the cover layer 40 has greater porosity and lowerdensity compared to the base layer 20 because the shoots from a grassseed are not as strong as the roots of the grass seed. The greaterporosity and lower density of the cover layer 40 permit the shoots fromthe grass seeds 50 to grow through the cover layer 40 withoutsignificant opposition and to permit adequate sun to meet with thecontained seeds 50. It is contemplated that the cover layer 40 be formedof a substrate that is as light and porous as possible, while stillmaintaining enough strength to not prematurely disintegrate or blowaway. On the other hand, the base layer 20 is a heavier, stronger anddenser product when compared to the cover layer 40. This denser and lessporous base layer 20 will retain the heat and humidity around the grassseed that aids in germination, while still being porous enough to allowthe roots of the grass seedlings to penetrate through it and mesh withthe ground. The strength of the base layer 20 also provides the seedbed10 with the support it needs until sufficient germination has occurredand the grass blades are viable.

In another embodiment, the layers 20, 40 are formed of the same materialas illustrated in certain examples in Table I. In these embodiments, thelayers 20, 40 surrounding the intermediate layer 30 can have the samebasis weight, wet density and porosity.

A raw pulp sheet could be used for either of the layers 20, 40. The pulpsheet provides the strength needed for the base sheet 20. The use of rawpulp sheets for either layer 20, 40 would allow the use of cellulosewithout the expensive and time consuming pulp converting stepconventionally performed on a paper substrate using a known method suchas airlaying. However, the chosen raw pulp sheet must be porous enoughand have a low enough density to permit the roots or shoots of the grassseed to penetrate through it and establish themselves.

The intermediate layer 30 includes seeds 50 and fertilizer 60. In anembodiment, intermediate layer 30 can also include other nutrients,growth and/or germination aids that may be desired for the growth of thegrass. The intermediate layer also receives the adhesive material usedto secure the base layer 20 and the cover layer 40 together around theintermediate layer 30 as they are secured together so that the seeds 50and fertilizer 60 are securely held in place within the seedbed 10 asdiscussed below.

The seeds 50 located within the seedbed 10 formed by any of theabove-discussed embodiments can be any known type of seed that meets theneeds of the end user. For example, the grass seed that forms a portionof layer 30 can be any known grass seed. However, the contained seed orcombination of different grass seeds will be dictated by the type ofgrass to be grown and the geographical location where the grass will beestablished. As understood, the grass seed used for a golf coursefairway will be different from the grass seed used for a putting greenon the same course. Similarly, the grass seed/seed mixture for a golfcourse in Georgia may be different from that used for an industrial parkin Oregon or a residential lawn in New Hampshire. Therefore, the grassseed mixture that forms layer 30 can differ from customer to customer,as well as, use to use for the same customer. The seeds used for thisproduct can be of varying types depending on the needs of the customer.In an embodiment, the dosing of seeds in the matrix will be on the orderof about 1 to 10 pounds per 1000 square feet of ground to be treated asset forth below: Grass Variety pound/1000 sqft Tall Fescue Blend 10Perennial Ryegrass Blend 5 Bluegrass/Ryegrass Mix 4 Bluegrass Blend 3Bentgrass 1

Other types of seeds, for instance those used for growing flowers andvegetables, could also be incorporated in with other types of seeds orreplace the grass seed within the seed bed. Additionally, embossing orlaminating the base layer 20 and the cover layer 40 so that at least twocompartments contain different seeds enable different vegetation to growfrom different compartments of the same seedbed 10. As a result, a usercan plant a pre-organized garden that will provide predetermined plantgrowth and a predetermined array of vegetation.

As discussed above, the intermediate layer 30 of seeds 50 and fertilizer60 is located between the bottom layer 20 and the cover layer 40. Theintermediate layer 30 can include those nutrients that assist in thegrowth and/or timing of germination for the vegetation, such as productsincluding peat and lime.

The fertilizers 60 can include natural or chemical fertilizers or otherknown additives that aid the growth process of the vegetation. Thefertilizer(s) can form part of the matrix of the total seedbed 10 bybeing introduced onto or into at least one layer 20, 40 of the seedbed10. For example, a fertilizer can be applied to a surface of the toplayer 40 that faces toward the base layer 20. In another embodiment, thefertilizer 60 can be applied to any surface of either of the layers 20,40. In yet another embodiment, the fertilizer 60 can be formed into oneof the layers 20, 40 during the production of the layers 20, 40. Anycombination of steps for applying fertilizer to the layers 20, 40 canalso be used.

More specifically, the fertilizer 60 can be added to the seedbed 10 bypouring or otherwise applying a granular or powdered fertilizer onto thebase layer 20 and in the same layer as the grass seed 50. In analternative embodiment, the fertilizer 60 takes the form of a liquidthat can be sprayed onto the base layer 20, the cover layer 40 or bothlayers 20, 40. In order to reduce production steps, the fertilizer 60can be sprayed onto the base layer 20 and/or cover layer 40simultaneously with the adhesive that is applied to these layers 20, 40before these layers 20, 40 are laminated together. For example, a liquidfertilizer could be mixed into the solution (potato starch) used to bindthe individual layers or into the glue used to laminate the substratestogether. Spraying of the fertilizer gives controlled, even distributionof the fertilizer. Controlled distribution can reduce fertilizer costsand provide more even growth. The liquid fertilizer 60 can also besprayed directly onto the seeds 50 so that it covers the seeds 50.

In an alternative embodiment, the fertilizer 60 can also be applied as acoating to the seeds 50 before the seeds are introduced into the seedbed10. Such coatings are disclosed in U.S. Pat. No. 6,209,259 to Madigan etal. and U.S. Pat. No. 4,753,035 to Ryan et al., both of which areexpressly incorporated herein by reference. The use of coated seeds 50can increase the ability of the manufacturer to control the amount offertilizer 60 introduced into the seedbed 10 for each seed 50. Coatingthe seeds 50 with a fertilizer and other nutrients also increases theproximity of the fertilizer 60 and other introduced nutrients to theseeds 50 in order to allow the seeds to use the nutrients moreefficiently and reduces the amount of fertilizer 60 and other nutrientsrequired. The fertilizer-coated seeds 50 also allow both seeds andfertilizer to be added to the product in one step, thereby reducing thenumber of production steps required to produce the seedbed 10.

In an embodiment, the fertilizer 60 has slow release nitrogen so thatthe initial sprouts from the seed will not be burned, and is high inphosphorus and potassium to provide stimulation for good rootdevelopment. As with the type of grass seed, the fertilizer 60 candiffer based on the needs of the client and the vegetation being grown.For example, one type of grass or seed may require a different ratio ofnitrogen, phosphorus and potassium than another type of seed. As aresult, the provided fertilizer 60 will change to complement the seedwithin the seedbed 10 that has been chosen in response to the needs ofthe customer. In an alternative embodiment, the nitrogen portion of thefertilizer 60 includes a controlled release product that will allow theturf to perform well during an extended portion of the growing season.In one embodiment, a nitrogen release term of 3-8 months is preferred.

In order to secure the seeds 50 and fertilizer 60 between the layers 20,40, the present invention includes the steps of securing the layerstogether along its outer edges, at multiple locations along theirinterior facing surfaces or over their entire interior facing surfaces.In an embodiment, a bonding agent is applied to the interior facingsurfaces of layers 20, 40 so that it holds these layers together as aunit after it has been laminated. As a result, the seed 50 will besecurely contained between the two layers 20, 40. The bonding agent caninclude any of the discussed biodegradable substances such as starches,modified celluloses or alcohol-based materials such as PVOH or PVA thatcan be used to secure two members together. Other conventional adhesivesthat could be used to secure the layers 20, 40 of the seedbed 10together or as binders for each airlaid layer include cellulose ethers,acrylics, EVA and EVA latex. It is also possible to use water as theadhesive or binding agent when used in combination with a wateractivated starch or other binder. Paper industry standard amounts of wetstrength resin used in airlaid, tissue and towel production can be usedin the bonding agent to provide a small amount of temporary wet strengththat could be useful for seedbed 10 integrity during the initialgermination period.

In an embodiment of the present invention, the layers 20, 40 can besecured together along the perimeter of one or both layers 20, 40 and atpositions that extend inward from the perimeters. In this embodiment,the inwardly extending lines along which the layers 20, 40 are securedtogether can create pockets within the intermediate layer 30 for holdingthe seeds for growing the desired vegetation. These pockets can includethe same seed(s), different seeds, a mixture of seed(s), fertilizerand/or nutrients for growing the desired vegetation(s). Accordingly,different vegetation can be grown using the same artificial seedbed 10.

In an alternative embodiment, the layers 20, 40 are secured together byembossing or perf-embossing. This would eliminate the use of water-basedadhesives that might require drying.

Referring now to FIG. 2, there is shown an apparatus and method formaking an artificial seedbed 10 according to the present invention.Biodegradable sheets of natural fibers for the base layer 20 and thecover layer 40 are moved in the direction of the arrows A, B,respectively. As discussed above, the seedbed 10 will be understood tobe made up substantially entirely of such natural fibers, although itmay contain a small proportion of synthetic fibers, which may beprovided in order to decrease the rate of decomposition of the resultingmat 30 when laid on the earth. The overall process according to anembodiment of the present invention will include making the individuallayers using desired techniques, and then marrying layers 20, 40together on the laminating line illustrated in FIG. 2. The cover layer40 and base layer 20 will not necessarily be matching materials. In anembodiment, the seedbed 10 includes a heavier base layer 20 (such as anairlaid product) and a lighter cover layer 40 (such as a wet laid tissueor towel). This will provide for good tensile strength while allowingthe grass shoots to penetrate the cover sheet 40 easily.

Once the layers 20, 40 have been formed, they are laminated togetheraround layer 30 as shown in FIG. 2. On the laminating line illustratedin FIG. 2, the adhesive will be added to the base layer 20. However, theadhesive could also be added to the cover layer 40 or both layers 20,40. The adhesive can be applied using either a spray header or bypassing the material of either or both layers 20, 40 through a coater.In an embodiment, a coater is used to apply a light coating of adhesiveto the base layer 20 that does not require oven drying of the seedbed10. However, it may be possible to pass the seedbed 10 through ahigh-temperature oven and drive off the majority of the water withoutraising the temperature of the seeds above the critical mark ofapproximately 140 degrees Fahrenheit. The liquid fertilizer may be acomponent of this adhesive and thereby applied simultaneously with theadhesive. As shown in FIG. 2, the seed can be added using a hopper-stylefeeder. The hopper will allow feed-rate adjustments so that the desiredseed distribution and density can be achieved. The adhesive will notonly allow the cover layer 40 to adhere to the base layer 20, but willalso secure the seeds to the bottom substrate 20. The seeds 50 should beadded as close as possible to the point where the cover layer 40 meetsthe base layer 20 along the lamination machine. This will quickly fixthe seeds in place and minimize material loss. If granular fertilizer isused, it can be added with a hopper feeder separate from that used forthe seed or in the same hopper as the seed. However, the changing sizeratios with different seeds could make it difficult to get an evendistribution of seed and fertilizer when using a seed/fertilizer mix ina single hopper.

After the addition of the seed 50, fertilizer 60, and the adhesive, thelayers 20, 40 are secured together. The laminating roll must be softenough to bond the substrates without crushing the seeds. The formedseedbed 10 can have a diameter and width that will be relativelyconvenient to handle. In one embodiment, the seedbed 10 may have adiameter of about 24 to 36 inches and a width of 72 inches(24-36″D×72″W). The size of the product will vary with its application.For example, a home-oriented product would likely be smaller and lighterthan that used for commercial or industrial application.

In another embodiment of a method for forming the seedbed 10, the seedsare applied onto a layer of loose paper fibers. Next, the seeds arecovered by a second layer of fibers and a binding adhesive is sprayedover the seeds and loose fibers in order to form a three layeredstructure that includes grass seeds positioned between two fibrouslayers having different density and porosity characteristics. In anotherembodiment, fibers that form a cover layer and seeds are bothsimultaneously released from a hopper and placed on a previously formedpaper base layer. Then, a binding agent is applied to secure the fibersof the cover layer that are mixed with the seeds to each other, theseeds and the base layer.

It is also possible that super absorbent polymers (SAP) could be addedto the seedbed 10 in order to provide a vehicle for supplying more waterto the seeds 50. However, this could increase production times andproduction costs. Also, a finished seedbed 10 with more than two paperlayers having separate seed and/or fertilizer types incorporated betweenthe various layers could also be formed. In another embodiment, thefertilizer 60 is added to the airlaid layer during the initialproduction of that layer in order to reduce the total number ofmanufacturing steps needed to form the seedbed 10.

In testing of the present invention, numerous layers of differentmaterials were produced. These layers included pulp sheets, tissue,towel, and airlaid products. It was found that in some embodiments thatairlaid substrates work well as base layers, but as cover layers theyhave a slower grass shoot penetration rate. In general, grass roots arebetter at penetrating a substrate than are grass shoots. Therefore, inan embodiment, a lightweight material, such as a tissue or towel, willlikely be used as the cover layer 40 and a porous heavier material suchas an airlaid substrate will likely be used as the base layer 20. Thisporous heavier material used as the base layer 20 can provide the neededstrength that the lightweight cover layer 40 cannot provide as well asbeing porous enough to allow the roots to penetrate through to the soil.

Samples of the seedbed 10 were developed and analyzed. In an embodiment,the seedbed 10 includes between about 4 to 8 pounds per 1000 square feetof fescue grass seed. However, as mentioned above, the seedbed 10 couldinclude between 10 and 12 pounds of seed per 1000 square feet. In thisembodiment, the seed is “STARFIRE” available from Columbia Seed Company.The fertilizer 60 in this embodiment includes Regal Liquid Green 12-6-12fertilizer applied to at least one of the layers 20, 40 at a rate of 32fluid ounces per 1000 square feet. The binding material used to adherethe layers 20, 40 together as a single unit about intermediate layer 30includes a biodegradable adhesive such as polyvinyl alcohol sold by H.B.Fuller under the name WB2746 polybond adhesive. This binding materialwas applied at a rate of one fluid ounce per 1000 square feet. The baselayer 20 and cover 40 were selected from the following table: SampleNumber Cover Layer 40 Base Layer 20 Sample 1 Tissue - 13 pounds per 3000Tissue - 22 pounds per 3000 square feet square feet Sample 2 Tissue - 13pounds per 3000 Airlaid - 100 grams per square feet square meter Sample3 Tissue - 13 pounds per 3000 Airlaid - 75 grams per square feet squaremeter Sample 4 Tissue - 13 pounds per 3000 Airlaid - 50 grams per squarefeet square meter Sample 5 Airlaid - 50 grams per Airlaid - 50 grams persquare meter square meter Sample 6 Airlaid - 75 grams per Airlaid - 75grams per square meter square meter

Any combination of these paper layers could be used in a single seedbed10. In the embodiments of the above samples (1-6), the airlaid sheetsare conventionally formed and bonded using “StructureCote” 1891 binderfrom Vinamul Polymers of Bridgewater, N.J. applied at about 7 to 10percent dry weight basis. The tissues set forth above in samples 1-4 areconventional wet laid materials manufactured without the addition of awet strength resin by a conventional wet-laid process. The towel wouldbe in a basis weight range of about 16 to 24 pounds per 3000 square feet(26-39 gsm) while the tissue could be at least as low as about 13 to 18gsm. Though hydrogen bonding will take the place of a separate binder,there still may be some need for low-level wet-strength chemicaladdition with the tissues and towels in order to provide addeddurability in rainy conditions during seed establishment. The 13-poundtissue is grade #65 from Georgia-Pacific Corporation(“Georgia-Pacific”). The 22-pound tissue is grade #68 fromGeorgia-Pacific.

Numerous additional samples of the seedbed 10 were tested. The resultsare shown in Table 1 and FIGS. 3-5 that include graphs 1-3. Sample #16was successful in that it had an 81% seed germination rate with an 81%seed penetration rate. This sample was constructed with a tissue top anda thermo-bonded airlaid material bottom. The combination of alightweight top sheet and a heavier bottom sheet seems to be aneffective combination of materials. The lightweight cover layer 40allows sufficient shoot penetration while the heavier base layer 20gives the seedbed 10 the strength it will need. Many of the samplestested had superior germination rates compared to the conventional“broadcast” seeding control sample.

Of the eighteen samples that were constructed and tested, with theexception of sample #7, each sample contained 192 SCOTTS ryegrass seedsand 0.5 g of 20-27-5 SCOTTS starter fertilizer sandwiched between thebase layer 20 and the cover layer 40. Sample #7 contained only 88ryegrass seeds and 0.25 g of 20-27-5 starter fertilizer (due to its sizeand shape). A potato starch solution was used to bond the sheets of thecover layer 40 to the base layer 20. The samples were constructed by 1)spreading the fertilizer over one of the layers 20, 40; 2) placing threeseeds per square inch onto one of the layers 20, 40; 3) sprayingapproximately 25 g of starch solution over the seeds positioned withinthe seedbed 10; and 4) placing the other of the layers 20, 40 of sheetover the seed 50 supporting layer and pressing firmly. The seedbed 10was then allowed to dry overnight.

After the samples dried, each sample was placed in a plastic tray (11inch diameter), which contained 1.5 inches of damp potting soil.Initially, each sample received 200 mL of water per day. However, theamount of water was later reduced to 100 mL per day. The sample trayswere placed under growing lamps for 12 hours per day. On a daily basis,the number of grass shoots that had penetrated the top sheet werecounted. General comments pertaining to each sample were noted, such asdevelopment of slime spots, cracks, and biodegradability. Aftertwenty-two days the experiment was stopped. Then, the total number ofshoots, including the ones that grew but did not penetrate through thecover layer 40, were counted and a percent germination was calculated.Table 1 contains a brief sample description, a construction descriptionand an overall rating of sample performance. Table 1 also containsinformation on the properties of the materials used to construct eachsample.

In FIG. 3, Graph 1 shows information pertaining to the number of shootsthat actually penetrated through the top sheet of the sample. In FIG. 4,Graph 2 depicts percent germination information. In FIG. 5, Graph 3depicts the modified percent germination information. To obtain thismodified percent germination information, the total number of seedsaffected by “slime spots” per sample was calculated. Then an adjustmentto the total number of seeds planted was made to account for the numberof seeds negatively affected by the “slime spots”. Example, sample #8developed a “slime spot” with a total area of 14.8 in². There are 3seeds per square inch. So, 14.8×3=44 seeds that were negatively affectedby the “slime spot”. Originally, each sample contained 192 seeds. So,192−44=148 modified total number of seeds for this sample. This modifiedtotal number of seeds would be used to calculate the modified percentgermination information. The slime spots were attributed to the level ofwatering provided to the seedbed 10, not the types of materials in whichthey appear.

While there have been shown and described and pointed out fundamentalnovel features of the present invention as applied to preferredembodiments thereof, it will be understood that various omissions andsubstitutions and changes in the form and details of the devicesillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit and scope of the invention asbroadly disclosed herein. TABLE 1 Wet Wet Construction Tensile DryCaliper Caliper BW Dry Density Density Porosity Overall Sample IDMaterial Description (Ns/cm) (mm) (mm) (gsm) (g/cc) (g/cc) (ft.3/min/ft)Rating 1. Control X X X X X X X 2. Paper Towel A Top & Bottom 2.7 0.530.33 50 0.09 0.15 29.80 Fair 3. Pulp Sheet A Top & Bottom 46.1 0.35 0.50150 0.43 0.30 N/A Poor Top 4. Blotter Sheet Top & Bottom 63.7 0.59 0.83273 0.46 0.33 N/A Poor Top 5. Pulp Sheet B Top & Bottom 69.7 0.63 1.04300 0.47 0.29 N/A Poor Top 6. Dexter Material Top & Bottom 6.8 0.36 0.4357 0.16 0.13 162.00 Good 7. Pulp Sheet C Top & Bottom 7.6 0.32 0.52 600.19 0.12 24.60 Fair 8. Reclaim Packing Top & Bottom 5.8 1.93 0.88 1690.09 0.19 43.00 Good Material (3 ply for both) 9. Pulp Sheet D Top &Bottom 27.0 0.27 0.41 100 0.37 0.24 N/A Poor Top 10. Hydro Entangled Top& Bottom 3.2 0.85 0.77 113 0.13 0.15 94.60 Fair Airlaid Material 11.Paper Towel B Top & Bottom 3.7 0.63 0.71 39 0.06 0.05 193.00 Excellent12. Paper Towel C Top & Bottom 2.4 0.64 0.71 71 0.11 0.10 119.00Excellent 13. Tissue A Top & Bottom 1.0 0.17 0.13 23 0.14 0.17 110.00Excellent 14. Towel D Top & Bottom 1.9 0.17 0.16 28 0.16 0.18 52.90 Good15. Airlaid Material A Top & Bottom 2.2 0.77 1.32 94 0.12 0.07 127.00Poor Top 16. Split Thermo Airlaid Material Separated 1.5 0.17 0.19 180.10 0.10 245.00 Excellent Material and Tissue Tissue Top & AL 0.9 0.791.00 80 0.10 0.08 312.00 N/A Pulp Mass Bottom 17. Airlaid Material A &BTAL Top & 300 gsm 2.2 0.77 1.32 94 0.12 0.07 127.00 300 gsm Pulp SheetBottom 69.7 0.63 1.04 300 0.47 0.29 N/A N/A 18. 100% Fluff Airlaid Top &Bottom 1.1 0.67 0.43 59 0.09 0.14 245.00 w/o Tissue

1. An article for use in growing vegetation, said article comprising: abase layer formed of a biodegradable natural fiber; a cover layer formedof biodegradable natural fibers having a wet density of no more thanabout 0.20 grams per cubic centimeter; and a biodegradable bonding agentfor securing said base layer to said cover layer.
 2. The articleaccording to claim 1 wherein said base layer has a basis weight of about23 to about 300 grams per square meter and the cover layer has a basisweight of about 13 to about 150 grams per square meter.
 3. The articleaccording to claim 2 wherein said base layer and said cover layer eachhave a basis weight of about 26 to about 80 grams per square meter. 4.The article according to claim 2 wherein said base layer and said coverlayer each have a basis weight of about 39 to about 71 grams per squaremeter.
 5. The article according to claim 1 wherein said fibers of saidcover layer are wood-derived cellulose fibers.
 6. The article accordingto claim 1 wherein said base layer comprises a pulp product.
 7. Thearticle according to claim 6 wherein said pulp product includes a sheetof a pulp product.
 8. The article according to claim 1 furthercomprising a plurality of seeds positioned between said cover layer andsaid base layer.
 9. The article according to claim 8 wherein at leastone of said seeds is coated with a fertilizer.
 10. The article accordingto claim 8 wherein at least one of said cover layer and said base layercarries a fertilizer for aiding in the growth of the vegetation.
 11. Thearticle according to claim 1 wherein said cover layer is secured to saidbase layer at positions spaced inwardly from outer perimeters of saidcover layer and said base layer such that a plurality of pockets areformed in said article between said cover layer and said base layer. 12.The article according to claim 11 wherein a first of said pocketscontains at least one seed for growing a first vegetation and a secondof said pocket contains seeds for growing a second vegetation.
 13. Thearticle according to claim 11 wherein a first of said pockets containsat least one seed and a second of said pockets contains fertilizerand/or nutrients for aiding in the growth of the vegetation.
 14. Thearticle according to claim 1 wherein said base layer has a wet densityof at least about 0.05 grams per cubic centimeter and the cover layerhas a wet density of about 0.05 to about 0.20 grams per cubiccentimeter.